Stabilizing high temperature operation and calendar life of LiNi0.5Mn1.5O4
Weiliang Yao,
Yixuan Li,
Marco Olguin,
Shuang Bai,
Marshall A. Schroeder,
Weikang Li,
Alex Liu,
Na Ri Park,
Bhargav Bhamwala,
Baharak Sayahpour,
Ganesh Raghavendran,
Oleg Borodin,
Minghao Zhang,
Ying Shirley Meng
Affiliations
Weiliang Yao
Materials Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA
Yixuan Li
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Marco Olguin
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA; Center for Advanced Research and Computing, University of Southern California, Los Angeles, CA 90007, USA
Shuang Bai
Materials Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA
Marshall A. Schroeder
Battery Science Branch, Energy Science Division, Army Research Directorate, DEVCOM Army Research Laboratory, Adelphi, MD 20783, USA
Weikang Li
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Alex Liu
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Na Ri Park
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Bhargav Bhamwala
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Baharak Sayahpour
Materials Science and Engineering, University of California San Diego, La Jolla, CA 92093, USA
Ganesh Raghavendran
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
Oleg Borodin
Battery Science Branch, Energy Science Division, Army Research Directorate, DEVCOM Army Research Laboratory, Adelphi, MD 20783, USA
Minghao Zhang
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA; Corresponding author.
Ying Shirley Meng
Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA; Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637, USA; Corresponding author at: Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA.
Severe capacity degradation at high operating voltages and poor interphase stability at elevated temperature have thus far precluded the practical application of LiNi0.5Mn1.5O4 (LNMO) as a cathode material for lithium-ion batteries. Addressing these challenges through a combination of experimental and theoretical methods in this work, we demonstrate how a fluorinated carbonate electrolyte enables both high-voltage and high temperature operation by mitigating the traditional interfacial reactions observed in electrolytes with conventional carbonate solvents. Computational studies confirm the exceptional oxidation stability of fluorinated carbonate electrolyte which reduces deprotonation at high voltage. The mitigated deprotonation will then minimize the formation of HF acid which corrodes the LNMO surface and leads to phase transformation and poor interphases. With fluorinated carbonate electrolyte at elevated temperature, it was found on LNMO’s subsurface a reduced amount of Mn3O4 phase which can block Li+ transfer and result in drastic cell failure. Leveraging this approach, LNMO/graphite full cells with a high loading of 3.0 mAh/cm2 achieve excellent cycling stability, retaining ∼84 % of their initial capacity at room temperature (25 °C) after 200 cycles and ∼68 % after 100 cycles at 55 °C. This advanced electrolyte also shows promise for improving calendar life, retaining >30 % more capacity than the carbonate baseline after high temperature storage. These results indicate that electrolytes based on fluorinated carbonates are a promising strategy for overcoming the remaining challenges toward practical commercial application of LNMO.
